COMBINED AND ECCENTRIC STRESSES 



S Standard Connection 



2l56"x4"x|' 



Force Polygon 



FIG. 80. 



STRESSES IN PINS. A pin under ordinary conditions is a 

 short beam and must be designed (i) for bending, (2) for shear, and 

 (3) for bearing. If a pin becomes bent the distribution of the loads 

 and the calculation of the stresses are very uncertain. 



The cross bending stress, S, is found by means of the fundamental 



Me 

 formula for flexure, 5* = , where the maximum bending moment 



M, is found as explained later ; / is the moment of inertia, and c is the 

 radius of a solid or hollow pin. 



The safe shearing stresses given in standard specifications are 

 for a uniform distribution of the shear over the entire cross section, 

 and the actual unit shearing stress to be used in designing will be equal 

 to the maximum shear divided by the area of the cross section of the pin. 



The bearing stress is found by dividing the stress in the member 

 by the bearing area of the pin, found by multiplying the thickness of 

 the bearing plates by the diameter of the pin. 



